Slide fastener stringer

ABSTRACT

A slide fastener comprises a synthetic-resin monofilament formed into undulations or turns and attached by a chain stitch to the support tape at only the legs lying along this tape. These legs are embraced by the stitches which are in part shielded by the remainder of the coupling element. The stitches may simultaneously form a filler cord and may be locked in place by clamping of the shanks of the coupling element thereagainst.

[ May 30, 1972 United States Patent Heimberger 54] SLIDE FASTENERSTRINGER 3,359,604 12/1967 Glindmeyer.. [72] Inventor: Helm HeimbergerGrenzach Germany 3,541,649 11/1970 y [73] 'Assignee: Opti-Hoiding AG,Glarus, Switzerland Nov. 27, 1970 [21] Appl. No.: 93,188

FOREIGN PATENTS OR APPLICATIONS 1,296,706 5/1962France............................24/205.l3C

[22] Filed:

Primary Examiner-Bemard A. Gelak AttorneyKarl F. Ross [30] ForeignApplication Priority Data Nov. 28,1969 German y A slide fastenercomprises a synthetic-resin monofilament formed into undulations orturns and attached by a chain [52] U.S. Cl...............24/205.1 C,24/205.16 C. 24/205.13 C [51] lm.Cl.....................................A44b 19 12 A44b 19 34 smchsuppmmpe the tape 24005 1 C 205 C 205 16C These legs are embraced by thestitches which are in part 58 Fi Id' 1 1 e o Scare shielded bytheremainder of the coupling element. The stitches may simultaneously forma filler cord and may be References Cited locked in place by clamping ofthe shanks of the coupling element thereagainst.

UNlTED STATES PATENTS 4 Claims, 5 Drawing Figures 2,910,755 Hansen.................24/205.13 C

PATENTEUMM 30 I972 SHEET 10F 4 ATTORNEY PATENTEnwao I972 3,665 561 SHEET2 or 4 HELMUT HEIMBERGER INVENTOR.

ATTORNEY PATENTED MAY 30 I972 SHEET 3 0F 4 FIG.4

HELMUT HEIMBERGER INVENTOR BY ATTORNEY PATENTEDMAY30 I972 SHEET 0F 4Helmuf Heimberger INVliN'IUR.

KM {Ross Attorney SLIDE FASTENER STRINGER FIELD OF INVENTION My presentinvention relates to slide fasteners and, more particularly, to a slidefastener having continuous coupling elements of the meandering or coiltype which are affixed to respective support tapes by rows of stitching.

BACKGROUND OF THE INVENTION Slide fasteners have been providedheretofore with support tapes upon which are mounted respective rows ofcoupling elements which are mutually engageable and disengageable uponthe movement of a slider therealong. The coupling elements may be coilsor meanders provided with closely spaced coupling heads adapted toengage between the coupling heads of the opposed element and produced,for example, from a continuous synthetic-resin monofilament, e.g. athermoplastic, such as a polyamide (nylon) or a polyester.

The tapes or support bands have been composed of synthetic resin orfabric and may be knitted or woven. Furthermore, various forms ofattachment have been used heretofore to affix each coupling elementalong the edge of the respective support tape of the slide-fastenerhalf. For example, knitted support tapes may have the coupling elementsincorporated into the fabric by knitting loops therearound or byproviding openings in the fabric into which the heads of the couplingelement are inserted. Woven support tapes may include the couplingelement as a wrap thread and may provide weft threads in engagement withthe bights interconnecting the coupling heads of the particular element.

More frequently, however, the coupling elements are secured by rows ofstitching, especially chain stitching, which passes over the shanks ofeach turn or meander of the coupling element and may, if desired, form aguide for the slider. Such systems have, however, the disadvantage thatmovement of the slider back and forth along the rows of the couplinghead or along the coupling elements causes wear of the stitchingaffixing the coupling elements to the support tape and eventualdeterioration of the slide fastener. Furthermore, since the rows ofstitching are exposed, they are subject to breakage and, indeed, thedeterioration of the system by which the coupling elements are affixedto the support tape, is a prime cause of breakdown of the slidefastener.

Mention may also be made, at this point, to the use of filler cordswithin the coupling element coil, in many cases, the rows of stitchingpassing through this cord. Also the stitching securing a couplingelement to the support tape may include stitch loops which pass througha cord lying alongside the coupling element (i.e. along a flank thereofopposite the coupling heads) and engaging loops of the meander or coilfrom which the coupling element is constituted. Systems in which thecoupling element is knitted or woven into the support tape are, ofcourse, of expensive manufacture whereas arrangements using filler cordshave likewise been complex in prior-art constructions of theslide-fastener stringers. As a result, principal attention has beendirected heretofore to the attachment of the coupling elements by rowsof stitches and, particularly, by chain stitching described earlier.Such stitching has the advantage that it can be relatively fine, therebyensuring a close spacing of the coupling heads of similar fineness as isdesirable in so-called invisible slide fasteners and wherever a no-snaghigh-quality closure is required. However, it has been found that theloops of the chain stitching which engage the shanks of the couplingelements and, especially those shanks which are spaced from the supporttape, have a tendency to slide rearwardly over the bight of the loops ofthe coupling element and loosen, while those stitches which overlie thecoupling element, are subject to wear as indicated above. As a result,the conventional methods of affixing continuous coupling elements tosupport tapes in slide-fastener stringers have many defects which havenot been eliminated by prior-art systems.

OBJECTS OF THE INVENTION It is, therefore, the principal object of thepresent invention to provide an improved slide fastener whereintheabove-mentioned disadvantages are obviated.

Another object of this invention is to provide a slide fastenerutilizing continuous couplingelements, namely, coils or meanders ofmonofilament synthetic resin, which provides a more secure attachment ofthe coupling element to the support tape.

It is also an object of the present invention to provide a slidefastener having the advantages of a filler cord but in which the fillercord, as a separate entity, may be avoided.

Yet a further object of the inventionis the provision of a slidefastener which will not manifest loosening of the attachment of thecoupling element upon breakage of a small number of attachment loops orthe breakage of the attachment thread.

It is an object of the invention further, to provide a slide fastener ofthe character described in which movement of the slider along thecoupling elements cannot wear away the attachment stitches.

SUMMARY OF THE INVENTION These objects and others which will becomeapparent hereinafter, are attained, in accordance with the presentinvention, with a slide-fastener stringer which comprises a pair ofsupport tapes and a respective continuous coupling element lying alongan edge of the support tape and so arranged and constructed that eachcoupling head of the continuous coupling element is associated with atleast one shank which lies against the support tape; the means forattaching the coupling element to the respective support tape includes arow of chain stitching with a loop thereof engaging each of the shanksresting upon the support tape and passing through the tape on oppositesides thereof while the loop itself lies within the coil space. In otherwords, each coupling element also provides shank portions of its turnsor meanders which lie above the shank portions seized by theaforementioned loops to define an interior of the coil or meanderthrough which the thread of the chain stitching passes. No threads ofthe chain stitching lie above the portions of the coupling elements mostdistal from the support tape.

The invention will probably be best understood in terms of a couplingelement in the form of a coupling coil, the latter being generally ahelix which may be somewhat distorted so that each turn forms anellipse, ovoid, keyhole or like shape. However, the invention isapplicable to meanders of the type having a space through which thechain stitching may pass. With coupling coils, each turn will have ashank lying against the fabric of the support tape and a shank spacedthereabove connected with the first-mentioned shank by a bight setinwardly from the edge of the support tape and with the lower shank ofthe next turn by a coupling head. The chain stitching of the presentinvention passes through the interior of the coil and engages only theshanks in contact with the support tape, i.e. the lower shanks.

According to a specific feature of this invention, the chain stitchingis a single-thread chain stitch, i.e. a form of chain stitching inwhich, as the needle is passed through the fabric, a loop former engagesthe thread on the opposite side of the fabric from that through whichthe needle is thrust. The loop former retains the loop until, at thenext stitch, the needle again carries the thread through this loop andat the same time pays out a fresh loop to be engaged by the loop former.When chain stitching of this type is used, the successive loops of thechain stitch engage around and partially cover the shanks of thecoupling element which lie against the support tape so that the entireseam is concealed within the coupling element.

As a consequence, wear of the chain stitching is obviated and theattachment stitching is fully concealed. Since the stitches cannot slipoff the coupling element, loosening is not a problem.

According to still another feature of this invention, the shanks of thecoupling element are clamped around and engage or are thermally bondedto the threads of the row of chain stitching passing through thecoupling element, the turns of the latter being appropriately deformedfor this purpose. This clamping and bonding action further preventsloosening of the attachment stitches, even In the event of breakage ofthe attachment thread, since the thread cannot pull out of the eyeformed by each turn. Moreover, the chain stitching fulfills the functionof a filler cord within the coupling element and restricts compressionof the latter.

DESCRIPTION OF THE DRAWING The above and other objects, features andadvantages ofthe present invention will become more readily apparentfrom the following description, reference being made to the accompanyingdrawing in which:

FIG. 1 is a diagrammatic perspective view illustrating the formation ofa slide fastener in accordance with the principles of the presentinvention;

FIG. 2 is a cross-sectional view illustrating the clamping engagement ofthe chain-stitch threads in accordance with the present invention;

FIG. 3 is a detail view showing other aspects of the formation of theslide fastener;

FIG. 4 is a view similar to FIG. 3 of another embodiment,

and FIG. Sis a view ofa portion of the slide-fastener half according tothe invention.

SPECIFIC DESCRIPTION In the following description, I have referred to amethod of and an apparatus for producing the slide fastener inaccordance with the present invention. This method and apparatus aremore fully described and are claimed in the commonly assigned copendingapplication Ser. No. 93,273 filed concurrently herewith by myself andKarl Griesbaum and entitled METHOD OF AND APPARATUS FOR PRODUCINGSLlDE-FASTENER STRINGERS.

In FIGS. 1 and 2 of the drawing, I have shown generally diagrammaticallythe principles of the present invention as applied to a helical coilcoupling element and the slide-fastener stringer incorporating same.

Basically, the stringer comprises a pair of slide-fastener halves, eachof which has a fabric support tape 1, a coil-tape continuous couplingelement 2 composed of a synthetic-resin monofilament, and attachmentmeans in the form ofa row 3 of general stitches traversing the supporttape 1. The coupling element, in turn, is formed with a plurality ofcoupling members generally designated at 4 and comprising coupling heads7 projecting beyond the edge 1a of the tape. The heads 7 have outwardlyprojecting portions 7a and 7b adapted to engage behind similar portionsof the heads of mating coupling members of the corresponding couplingelement formed on the other tape of the stringer. The head 8 is providedby kinking the monofilament 2 at 8, for example, after a preliminaryflattening of the filament. The shafts 6a and 6b extend rearwardly fromeach head 7 of a particular turn 4 and are joined by a bight 9 to theturn of a succeeding and preceding coupling head respectively. Theshanks 6a lie against the tape 1 while the shanks 6b are disposedthereabove. Between the shanks and within the coil there is formed aneye-shaped space Oe constituting the interior ofthe coil.

As best seen in FIG. 1, moreover, the chain stitching is of thesingle-thread type wherein a loop is formed above the tape 1 bythrusting the needle 40 of the chain-stitch sewing machine upwardlythrough the tape, a loop 31 being formed by engagement of a loop-former42 with the thread as the needle is ,withdrawn. The loop 5, 31 isstretched over each shank 6a as it is laid in place upon the tape 1 andis engaged, in turn, by the upwardly carried thread of the needle which,upon its subsequent introduction through the tape, passes through thisloop. Hence, a double strand of the thread ofthe chain stitch 3 overlieseach of the shanks 6a and retains it against the tape and passes throughthe latter on either side of the shank. The row 30f chain stitches lieswholly within the interior Oe of the coupling-element coil and isshielded by the shanks 6b against deterioration.

As also can best be seen from FIGS. 1 and 2, each coupling member isheld in place by a respective loop 5 of the chain stitch. In theconventional manner, end-stop members can be formed at the end of eachcoupling element, e.g. by the thermoplastic deformation of the couplingelement and plug-andsocket members may be provided in the conventionalfashion when separable slide fasteners are to be produced. The slider isapplied in the usual manner, and upon movement along the couplingelements, brings both of the elements of the two slide-fastener halvesinto mating engagement or separates them from one another.

As best seen in FIG. 2, the upper shank 6b can be pressed downwardly,e.g. by a forming roller 43 which may be connected, as shown at 44, to asource of ultrasonic welding energy, while being constituted as anultrasonic welding electrode or sonotrode. The shanks 6a and 6b arethereby clamped at 10 and thermally welded together against the twostrands of the chain-stitch thread to lock each loop 5 and preventrelease of the coupling element upon breakage of the stitch at any pointor against withdrawal of the single-thread chain stitch. The othermember of the ultrasonic welding assembly can be an anvil underlying thetape as shown at 44. The ultrasonic welding operation simultaneouslyconstitutes a thermal fixing of the coupling element in its deformedstate as shown in FIG. 2.

The production of the slide fastener half according to the presentinvention is detailed at FIG. 3 which shows the apparatus in somewhatsimplified form. It should be understood that the apparatus consists ofan ordinary chain-stitch sewing machine and the various members of theapparatus, which are moved in synchronism, can be coupled with a camdrive of the sewing machine by conventional means. The apparatuscomprises an upper transport comb 11 and a lower transport comb 12 whichare periodically withdrawn, reinserted and shifted in the direction ofarrow 17 and are provided with teeth 11a and 12a, respectively, engagingbetween the turns 4 of the coupling element.

To the main shaft of the chain-stitch sewing machine is connected, viaan eccentric drive, the shaft 19 of a swinging lever 13, the axis ofwhich is represented at A and lies parallel to the transport directionrepresented by the arrow 17 but which underlies the sewing machine tableonly partly illustrated at 18 in FIG. 3. The lever 13 is of generallyC-shaped caliper or yoke configuration with a bent arm on 21 extendingfrom below upwardly around the tape 30 and provided with an eye 22through which the monofilament 2 is fed.

In addition, the apparatus comprises retaining fingers 14 and 15 whichare mounted on pivoting shafts 14a and 15a respectively coupled with thecam drive and serving to retain the monofilament 2 during each swing ofthe arm 21 to and fro across the tape 30. The finger 15 thus forms thebight while the finger 14 forms the head of each coupling turn 4. Finger14, moreover, may press with sufficient force to deform the head 7 asalready noted. Assume, therefore, that the system is in the positionillustrated in FIG. 3, i.e. with the needle 40 penetrating the tape 30and forming the beginning of a loop 32 which is engaged by the loopformer 31. At this instance, the filament 2 is stripped across the tape30 and is retained by the finger 15 while the finger 14 preparatorilyimpresses the filament to deform the latter preliminary to the return ofthe eye 22 in the counterclockwise direction. As the needle descends anddisengages from the tape 30, the transport mechanism advances the tapein the direction of arrow 17 by a distance corresponding to one stitchand one turn of the coupling element, thereby stretching the loop 32across the filament. The eye 22 then carries the filament again acrossthe tape to form the upper shank as the needle is thrust upwardly toengage the loop. The process is repeated over the length of the supporttape. The kink formed at 33 produces the head.

In FIG. 4, I show a system wherein in place of the finger 15, a mandrelM is employed in the shaping of the coupling coil. It will beunderstood, however, that similar principles can be used to producemeandering coupling chains Furthermore, the apparatus can be doubled toform two slide-fastener halves simultaneously so that the opposingcoupling elements can be interconnected in the production of theslide-fastener stringer. Each coupling element can be affixed to therespective support tape with several needles in, for example, theproduction of one-needle, two-needle, three-needle chain-stitch rows.The term stitch, therefore, is not intended to limit the number ofneedles with which the stitches are formed. In FIG. 5, I show a finishedportion of a slide-fastener half in which the upper shank of each turnis fused to the lower shank as described previously in connection withFIG. 2. The depressed rear portions of the upper shank can be seenclearly at 6b in this Figure.

The improvement described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art, all suchmodifications being considered within the spirit and scope of theinvention except as limited by the appended claims.

I claim:

1. A slide-fastener stringer half, comprising a support tape,

a continuous coupling element formed with a plurality of couplingmembers matingly engageable with the coupling members of an opposingslide fastener half and having respective shanks lying along said tape,a row of chain stitches fastening said coupling element to said tape andincluding a respective loop extending over each of said shanks, saidcoupling element being a coil of a synthetic-resin monofilament and eachof said members of said coil includes a coupling head, a lower shankextending from said head along said tape and an upper shank extendingfrom said head above said lower head and defining the interior of saidcoil, said loops passing over only said lower shank and said row beingformed within the interior of said coil.

2. The slide-fastener stringer half defined in claim 1 wherein said rowof chain stitches is a single-thread chain stitch and each of said loopshas two strands engaging the respective lower shank.

3. The slide-fastener stringer half defined in claim 2 wherein each ofsaid upper shanks clamps a respective loop against the correspondinglower shank.

4. The slide-fastener stringer half defined in claim 3 wherein each ofsaid upper shanks is fused to the respective lower shank in the regionin which said loop is clamped.

1. A slide-fastener stringer half, comprising a support tape, acontinuous coupling element formed with a plurality of coupling membersmatingly engageable with the coupling members of an opposing slidefastener half and having respective shanks lying along said tape, a rowof chain stitches fastening said coupling element to said tape andincluding a respective loop extending over each of said shanks, saidcoupling element being a coil of a synthetic-resin monofilament and eachof said members of said coil includes a coupling head, a lower shankextending from said head along said tape and an upper shank extendingfrom said head above said lower head and defining the interior of saidcoil, said loops passing over only said lower shank and said row beingformed within the interior of said coil.
 2. The slide-fastener stringerhalf defined in claim 1 wherein said row of chain stitches is asingle-thread chain stitch and each of said loops has two strandsengaging the respective lower shank.
 3. The slide-fastener stringer halfdefined in claim 2 wherein each of said upper shanks clamps a respectiveloop against the corresponding lower shank.
 4. The slide-fastenerstringer half defined in claim 3 wherein each of said upper shanks isfused to the respective lower shank in the region in which said loop isclamped.